Internal combustion engine



Sept. 29, 1931. v w. w; MARVI I 1,825,278 7 INTERNAL COMBUSTION ENGINE Filed Dec. 29, 1923 z sneus-sneex 1 INVENTOR.

ATTORNEY.

Sept. 29, 1931.

w. w. MARVIN INTERNAL COMBUSTION ENGINE Filed Dec. 29. 1928 2 Shg'ets-Stpot 2 INVENTOR.

A TT ORNE Y.

Patented Sept. 29, 1931 UNITED STATES PATENT OFFICE WARD W. MARVIN, OF ROYAL OAK, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, 'IO JANE STUART MARVIN, OF ROYAL OAK, MICHIGAN INTERNAL COMBUSTIQN ENGINE Application filed December 29, 1928. Serial No. 328,132.

The present invention relates to internal combustion engines more especially to two cycle multicylinder engines.

Among the objects of the invention is the reduction in size and weight of such engines while at the same time increasing their efficiency.

Another object is to eliminate some of the parts now considered necessary and thereby reduce both weight and friction.

Other objects will readily occur to those skilled in the art upon reference to the following description and the accompanying drawings in which Fig. 1 is an end elevation of the engine with parts in section and with one cylinder broken away.

Fig. 2 is a vertical section through one of the cylinders on a plane at right angles to the plane of Fig. 1.

Fig. 3 is a section on line 3-3 of Fig. 1.

As indicated in the drawings the crank case of the present engine is rectangular and preferably square and is indicated at 10 with four cylinders 11 mounted thereon at the four sides. These cylinders will preferably be in the same plane and centrally located with respect to the crank shaft 12 which passes through the crank case and is provided with suitable bearings therein.

The crank shaft is shown as being provided with a single throw upon which will be mounted two square blocks 15 each preferably formed in two halves and each preferably formed with guiding ribs 16 whereby the blocks may be retained against lateral movement each in its respective Scotch yoke 17. There will be two of the Scotch yokes 17, one for each pair of opposed cylinders and to each of the yokes is fixed a semi-cylindrical member 20 as by means of cap screws 21, extending from the long sides of the yokes. Each of the members 20 carries at its outer end a piston 25, which is adapted to coact with a cylinder 11 and operate therein.

The crank case 10 will be provided on its inner walls with four flat guide members 30 for the two yokes, these guide members being adapted to cooperate with the short two cycle type and each piston 25 may be supplied with previously compressed gases from the crank case to the compression chamber 50 through the openings 51 in piston 25 when the latter is at its top position. When, due to the explosion of a previous char e in space 55, piston 25 is driven downwar and reaches its lowest position, the gases are further compressed in the chamber 50, flow out through the opening 52 into the passage 53 and through the opening 54 to the space 55 above the. piston 25, being deflected upwardly in the usual manner by the ridge or lip 56 and exhausting at exhaust tube 57 after having been exploded in space 55.

By making the engine of the construction indicated, it is possible to place the four 0 linders in the same plane and to use a single throw crank shaft upon which all act and by using the Scotch yoke construction it is possible to entirely overcome lateral pressure of the pistons against the cylinder walls, both in the case of the pistons 25 and 32.

Now having described the invention and the preferredform of embodiment thereof, it is to be understood that the said invention is to be limited not to the specific details herein described and illustrated, but only by the scope of the claim which follows:

I claim An internal combustion engine of the multi-cylinder two-stroke cycle type comprising a square crankcase, a cylinder on each side thereof, a single-throw crankshaft extending therethru, a movable hollow piston in each of said cylinders, the pistons in opposed cylinders being connected to each other, a stationary piston inside each of said movable hoIlow pistons, the hollows forming compression chambers in said movable pistons, a Scotch yoke midway of each connecting means and adapted to actuate the shaft, and means in said crankcase furnishing lateral guides for said Scotch yokes.

WARD W. MARVIN. 

